Where you change /var/www/my_site to be the correct path to your Bolt
installation.

Then in config.yml you need to set the cron_hour parameter. The parameter
takes an integer between 0 and 23, representitive of the hour of the day you
want the daily, weekly, monthly and yearly tasks to execute at. By default is
set to 03:00 am.

cron_hour: 3

Important Information for Timed Record Publishing

If you are using the cron to publish timed records (which is highly recommended) then
you need to set a flag in your config.yml or config_local.yml.